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Week 4: ESA Archaeological research in East Africa: new data & new questions
Map of East African early hominid sites
So far, we’ve done a brief comparison of the geological and environmental context of sites in South Africa and East Africa. Now we’re going to look at what was found at sites in more detail, and the questions about how to interpret them… how we can use archaeological sites to make inferences about the behavior of early hominids.
On the one hand, archaeologists have the opportunity to look at sites as evidence of hominid activities. Once early hominids started breaking rocks, they left behind a durable record of their behavior. Each site marks the spot where debris accumulated… sometimes the actual locations where activities took place (in situ sites)… the "calling cards" of the stone age. This gives us the opportunity to analyze what hominids did, and when and where… from there we can pursue questions of how and why.
Step 1 = Using the CD-ROM, look at the artifacts at FLK-Zinj.
= Broken stones
- Why do archaeologists conclude that the artifacts at FLK-Zinj were manufactured or used, and not just broken rocks that occured naturally at the site? (e.g. how to avoid the problem Dart had with the osteo-donto-keratic?)
- What were they used for? What is the evidence for this?
- How sophisticated are the artifacts? Do they range in complexity of manufacturing technique, or degree of planning-ahead?
- How variable are they? e.g. any differences in types of artifacts from different raw materials?
Who made these artifacts? What is the logic behind this hypothesis?
Last time we started looking at the nature of the artifacts discovered at FLK-Zinj. (I hope you’ve continued to read about the artifacts in the assigned readings. In particular, for technology, read the Toth article and the Isaac article. The Leakey article summarizes other sites at Olduvai other than FLK.)
To summarize the points you made in class Tuesday, you noted that:
The artifacts were broken stones, hammerstones and unmodified stones
- With distinctive fracture patterns that suggested deliberate flaking
- With some evidence of use-wear and damage
- Made from a variety of raw materials that were imported to the site, some from as far away as 8 km
Functionally, they could serve as cutting, scraping or pounding/crushing tools
Who dunnit? You made arguments based on:
- How function of tools (e.g. cutting or pounding) would relate to inferred dietary needs of hominids (e.g. meat or nut-cracking)
- How technological simplicity of tools would relate to evidence for dexterity (both hominids had hands that could probably make and use these Oldowan tools)
- How technological simplicity of tools would relate to evidence for mental ability (do the different brain sizes of the hominids imply that Homo would have been more likely to create and use stone tools?)
This gets to one of the central questions archaeologists worry about: what can the artifacts show about the mental and cultural abilities of the hominids? To answer this, we need to be able to analyze how the different types of tools at such a site were made and whether they reflect any deliberate "designs" by the hominids, or whether they were opportunistic.
Remember Mary Leakey’s Oldowan typology? She distinguished between flaking debris and informally utilized pieces, and tools that she thought were actually designed to be specific shapes, because of how they were made. For example… chopper versus discoid
And she argued that she could recognize sites with assemblages with suites of tools that were so different that they could represent different "cultures" of hominids… e.g. different traditions of tool making by different social groups of hominids. (see the article by Leakey in the readings).
Oldowan assemblages
Developed Oldowan assemblages (include more of the fancier tool types, like spheroids and proto-bifaces)If you look at Leakey’s descriptions of different assemblages of tools from different sites at Olduvai, you’ll see %’s of many different tool types. The question is: does this reflect actual mental templates of ancient hominids, or are we applying modern human desire to classify (to put things in pigeon holes) to a bunch of simply broken rocks?
An alternative classification scheme was developed by Glynn Isaac and Nick Toth that was based on experimental studies and instead of assuming different tool types existed, focused on the technology of how they were made…. Least effort assumption that goal of flaking was flakes… e.g. sharp edges. Their categories of artifacts determined essentially by physics of stone fracture
Flaked Pieces
Detached Pieces
Pounded Pieces
Unmodified Pieces
Within these categories they noted a regularity of pattern.. e.g. appear to reflect morphological or functional goals, not just expedient flaking. Such as "Karari scraper"
From this "core + flake" perspective, the Oldowan sites look much simpler, and perhaps more similar to each other. This places the burden of proof on the archaeologist to demonstrate that tool "designs" are not just by-products of an opportunistic flaking process. Rick Potts adopted aspects of this approach in his interpretation of sites at Olduvai (see assigned article).For example:
- Can you demonstrate that different raw materials were used in different ways? Were different strategies employed to flake different types of rock? (possible selection of specific raw materials for specific purposes?)
- Can you find evidence that cores were actually deliberately used for specific purposes, and not just sources of flakes?
- Can you find changes in technology through time that might suggest developing or different traditions of tool use?
What are key abilities needed to do percussion flaking?
- Knowledge that sharp flakes break off if you strike edge of rock
- Knowledge of types of rocks that flake well
- Hand-eye coordination to strike edge of core with precision and power
Experimental work with Kanzi and other chimps: Experiments by IU researchers Nick Toth, Kathy Schick and Gary Garufi with captive chimpanzees have demonstrated that chimps can also learn to use flakes as sharp knives, and learn to flake stone cores.
They can PERFORM well (VIDEO)
- Taught concept of "sharp rock"
- Taught goal of breaking rock to create sharp edge
- Taught how to flake, and with practice can produce impressive flakes, although have not yet demonstrated patterns of flaking single core analogous to Oldowan choppers, etc.
- Can strategically outwit scientists to get the goods!
In wild:
Chimpanzee comparisons: apes in the wild learn to use a wide range of tools... as described in the article by Whiten et al. (PDF version with color illustrations)
- Chimps use a wide range of tools for different tasks, but no cutting tools
- Many different types of raw materials used … how does this compare with what has been preserved for archaeological sites?
- Some populations of chimps in W. Africa use hammerstones and anvils to crack nuts (VIDEO)
- Considerable dexterity and power directly analogous to skills needed to crack rocks… can control hammerstones over 40 lbs!!
- Techniques and specific toolkit are learned by young animals, and vary between groups in different regions (we’ll explore next week)
Want to learn more about chimpanzees?
- Chimpanzee Cultures Online (access to searchable database by Whiten et al)
- online paper by Craig Stanford about chimpanzee hunting
- African Ape Study Sites by Jim Moore, UC San Diego (wonderful descriptions and images of the wide range of chimpanzee and gorilla research sites in Africa)
- Bossou study site
- Jane Goodall Institute
Jane Goodall at Gombe National Park, Tanzania
Now: go down to lab to look at examples of Oldowan tools and see some flaking (last 20 minutes)
Professor Jeanne Sept (812) 855-5395 ; email: SEPT Office Hours Student Bldg 038 TH 1:00-2:00, or by appt.
TuTh 11:15-12:30
